This invention relates generally to circuitry for combining or dividing power and, more particularly, to power combiners and dividers used in communication systems at microwave frequencies.
The conventional technique for dividing power in communication system is to employ passive electrical networks, such as Wilkinson dividers, each of which produces two nominally equal outputs from a signal input. Such networks can be cascaded to produce larger numbers of output ports from a single input. In this specification, operation will be described first in terms of power dividing, but it will be understood that each circuit described can be operated in an inverse manner to perform a power combining function.
In cascaded passive networks of the Wilkinson type, there is a substantial loss of energy from one stage to the next, and the size and weight of the network are dependent on the divide ratio (N) and the frequency of operation. In systems requiring power division over a wide band of frequencies, involving multiple octaves, the use of large N-way dividers can limit system performance due to high insertion loss, and large size and weight.
Ideally, what is needed for use in microwave communication systems is a power divider and combiner that is small in size, light in weight, has low insertion loss, and is capable of providing a high divide ratio over a wide frequency band. The present invention is directed to this end.